Generally, a valve timing control apparatus is configured so that a relative angle of a driven-side rotating member is changed in a manner where a fluid control mechanism is controlled so that an amount of an operation fluid within a retarded angle chamber and an advanced angle chamber is changed. Accordingly, an opening and closing timing of a valve is adjusted, so that an amount of air suitable to a driving condition is suppliable/dischargeable relative to an internal combustion engine.
For example, a valve timing control apparatus disclosed in JPH07-139380A includes a variable valve timing mechanism, a driving state detecting means, a valve timing determining means, a driving control means and a driving speed condition determining means. The variable valve timing mechanism is torsionally driven in order to continuously vary an opening and closing timing of at least one of an intake valve and an exhaust valve. The driving state detecting means detects a driving state of an internal combustion engine. The valve timing determining means determines a valve timing target value on the basis of a detection result of the driving state detecting means. The driving control means controls an actuation of the variable valve timing mechanism on the basis of the valve timing target value in order to control the opening and closing timing of at least one of the intake valve and the exhaust valve. The driving speed condition determining means determines whether or not a speed should be changed on the basis of a detection result of the driving state detecting means. Furthermore, the driving control means is configured so as to stop the control of the valve timing to correspond to the valve timing target value in response to the driving state during a period of time from when a speed shift is started until the speed shift is ended on the basis of a detection result of the driving speed condition determining means. Still further, the driving control means is configured so as to execute a control of the internal combustion engine on the basis of a maximum cam phase target value, which is set in an operation state at a point of time when the speed shift is completed, in a direction reverse to a direction where the variable valve timing mechanism is moved by a cam rotational torque as a target value.
According to the valve timing control apparatus of the internal combustion engine disclosed in JPH07-139380A, the control is executed on the basis of the maximum cam phase target value in the direction reverse to the direction in which the variable valve timing mechanism is moved in response to the cam rotational torque upon the driving condition when the speed shift is completed, instead of the target value corresponding to the driving condition, during the period of time when the speed shift is started until the speed shift is completed. Accordingly, a responsiveness of the valve timing control apparatus while the shift speed is changed may be increased.
A control apparatus for a variable valve mechanism disclosed in JP2009-085139A includes a variable valve mechanism, a target value calculating means, a reference response value calculating means, a feedforward control amount calculating means, a feedback control amount calculating means, and an operation amount calculating means. The variable valve mechanism is configured so as to change a valve opening characteristic of an engine valve. The target value calculating means calculates a target value of the variable valve mechanism corresponding to a target value of the valve opening characteristic of the engine valve. The reference response value calculating means calculates a reference response value in a case where the variable valve mechanism is actuated in response to a reference response characteristic. The feedforward control amount calculating means calculates a feedforward control amount for responding the variable valve mechanism on the basis of the reference response characteristic. The feedback control amount calculating means calculates a feedback control amount for eliminating a deviation between the reference response value of the variable valve mechanism and an actual response value thereof. The operation amount calculating means calculates an operation amount outputted to a driving means of the variable valve mechanism on the basis of the feedforward control amount and the feedback control amount. Furthermore, the variable valve mechanism disclosed in JP2009-085139A includes a deviation calculating means for calculating the deviation between the target value of the variable valve mechanism and the reference response value thereof, and an integration calculation terminating means for terminating a calculation using an integral element when the feedback control amount is calculated, in a case where the deviation between the target value of the variable valve mechanism and the reference response value thereof is equal to or greater than a predetermined value.
According to the variable valve mechanism disclosed in JP2009-085139A, the calculation using the integral element when the feedback control amount is calculated is terminated when the deviation between the target value of the variable valve mechanism and the reference response value thereof becomes equal to or greater than the predetermined value. Accordingly, an overshoot occurring as a result of an integral value becoming excessive may be avoided, so that the reference response value is smoothly converged into (corresponds to) the target value.
According to the valve timing control apparatus of the internal combustion engine disclosed in JPH07-139380A and the variable valve mechanism disclosed in JP2009-085139A, the opening and closing timing of the valve under a normal driving condition may be appropriately controlled. However, a control to be executed when a vehicle is suddenly accelerated is not considered. Therefore, even if the control disclosed in JPH07-139380A and JP2009-085139A is adapted in the case where the vehicle is suddenly accelerated, a sufficient acceleration performance may not be achieved.
A need thus exists to provide a valve timing control apparatus which is not susceptible to the drawback mentioned above.